Door latch mechanism



June 7, 1969 I; I I r 5 f 9 llmmm Mia I RICHARD PERL United StatesPatent 3,450,851 DOOR LATCH MECHANISM Richard L. Perl, Mansfield, Ohio,assignor to The Tappan Company, Mansfield, Ohio, a corporation of OhioFiled Apr. 13, 1966, Ser. No. 542,391 Int. Cl. HOlh 13/52 US. Cl.200-61.68 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates asindicated to a latch mechanism for doors and particularly doors such asthose used in automatic dishwashers which are required to exert asealing force when closed, usually against a gasket or other deformablesealing element.

It is a primary object of the invention to provide a door latchmechanism which has a superior locking action and yet can beconveniently and easily released for opening of the door.

Another object is to provide such latch mechanism having a push buttonrelease, with this form of actuator in a front loading automaticdishwasher, for example, having the advantages of minimum and regularprojection at the front of the door, extremely convenient location andmanipulation, and simple clean design from the standpoint of appearanceof the appliance.

It is also an object of the invention to provide a latch for dishwasherdoors and the like which is relatively inexpensive and readilyincorporated in existing designs for such machines.

It is a still further object to provide latch mechanism for a doorincluding electric switch actuating means to provide a related switchingfunction, for example, to interrupt operation of an automatic dishwasherresponsive to opening of the door.

It is further desirable in such a dishwasher that the such switchcontrol be somewhat anticipatory of actual opening of the door toprovide at least a brief interval for decay of the particular operatingcondition which may be interrupted, such as a water spray, and it isstill another object of this invention to incorporate such ananticipatory switching function in the door latch mech anism to the endthat the interruption is effected almost immediately upon initialmovement of the release member and before full disengagement of thelatching mechanism.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawing setting forth in detail a certain illustrativeembodiment of the invention, this being indicative, however, of but oneof the various ways in which the principle of the invention may beemployed.

In said annexed drawing:

FIG. 1 is a front elevation of an automatic dishwasher the door of whichis equipped with latching mechanism in accordance with the presentinvention;

3,450,851 Patented June 17, 1969 FIG. 2 is a fragmented sectional viewof the portion of the machine in which the latch is located, the planebeing indicated by the line 2-2 in FIG. 1;

FIG. 3 is a further sectional view taken on the plane of the line 3--3in FIG. 2; and

FIG. 4 is a fragmentary top view of the mechanism with parts broken awayfor convenience of illustration.

Referring now to the drawings in detail, the automatic dishwasher shownin FIG. 1 is of conventional construction apart from the door latchmechanism to be described, with this machine having a front door 10hinged at the bottom to move between the vertical closed conditionillustrated and a substantially open horizontal position. The door has adecoratively formed top strip 11 projecting forwardly and downwardlywith a free rolled lower edge 12 and serving as a handle for the door.The door of this machine is also provided with an upper control panel 13just below the handle portion 12, with knobs 1'4 and push buttons 15 forscheduling the automatic operation in conventional manner.

As best shown in FIG. 2, the tub 16 of the dishwasher has a frontboundary wall portion 17 in a vertical plane, with this portionextending continuously about the sides and top and opposed to theperipheral portion 18 of the door in accordance with conventionalconstruction. As is also conventional, the inner liner 19 of the doorprojects inwardly from such peripheral portion to enter the tub andsealingly engage an elastomeric gasket 20 fixed to the tub interior andalso extending continuously about the sides and top.

A specially formed strike is fixed to the tub at the top center of theframing wall portion 17, with a stem 21 shown threaded in theillustrated embodiment penetrating this wall portion and being locked byan exterior nut 22 and an interior spring nut 23 acting oppositelyagainst the wall portion. This strike has a relatively flattenedsubstantially triangular head 24 at its outer end, with such head beinghorizontal and symmetrically related to the stem as shown to have apoint foremost and base shoulders 25 projecting laterally to therespective sides of the contiguous stem portion 26. The edges of thisstern portion 26 converge slightly outwardly to the junctures with thebase shoulders 25.

The keeper assembly of the latch is mounted within the top interior ofthe door on a bracket 27 suitably affiXed to the inner door liner. Thisbracket is cut and bent or otherwise formed to provide a top edge flange28 projecting forwardly, a similarly projecting middle or inter-mediateflange 29 at a lower elevation, and a lower body section 30 which isdisplaced forwardly relative to the upper section and has a smallforward bottom flange 31. A wire hairpin spring is supported on thebracket 27 in the inverted condition shown in the drawing, with theclosed end or loop 32 resting on the bottom flange 31 of the bracket andagainst its lower body section 30. This closed end portion of the springis restrained by small angles 33 struck from the body section to projectforwardly at two opposite points inside the loop and then laterally overthe spring at these portions, so that the thus restrained spring is freefor expansion or spreading of its two arms 34 which are normallysubstantially parallel over their major extents.

The intermediate bracket flange 29 has a pair of aligned slots in itsside edges and the arms 34 of the spring extend upwardly respectivelythrough these slots. A roller 35 is applied to the end of each arm ofthe flange, so that there are two such rollers normally held insubstantially parallel vertical relation and spaced slightlyrespectively to the sides of the axis of the strike in the approach ofthe latter.

The length or vertical dimension of the rollers 35 is appreciablygreater than the thickness of the strike head 24 and the arrangement issuch that the latter is directed approximately half way between the topsand bottoms of the rollers. It will be clear that bringing the door froman open to the closed condition advances the spring roller keeperassembly on the strike, an opening 36 of course being provided in theinner door liner 19 for penetration of the door by the strike. Thestrike head 24 enters the normal small space between the rollers 35 and,with continued closing movement, the relatively diverging side edges ofthe head force the rollers apart against the tension of the spring arms34 until the rollers pass over the base corners 25 and are snapped inagainst the stem portion 26 of-the strike behind these corners orshoulders. This is the fully closed and latched condition of the doorillustrated in the drawing, and it will be appreciated that theprojection of the strike is adjusted to provide the proper amount ofrelative travel thus to latch the strike with the desired pressureexerted by the door against the sealing gasket. It has been found thatthe shoulders of the strike head should preferably be normal or at rightangles to the stem axis for the degree of restraint desired in anapplication of the latch mechanism to such a dishwasher door.

The release of the latch is effected by a push button member, designatedgenerally by reference numeral 37, disposed horizontally to extend fromthe spring rollers 35 forwardly through an opening 38 in the front wallof the door handle 11, with the exposed outer end 39 of such memberthereby being conveniently available to the housewife or user, forexample, to be depressed by the thumb of the same hand of the user whichgrasps the handle to pull the door open. This member, which .can be mosteasily made of molded plastic, has an intermediate body section 40 justbehind the handle wall of larger cross section than the projecting outerend 39 and the opening 38 through which the latter extends, so thatthere is a resulting shoulder which serves as a stop precludingwithdrawal of the member from the door. Inwardly of this section, themember 37 is formed with similar top and bottom finger extensions 41 ofwedge shape which are vertically spaced apart a distance appreciablygreater than the vertical dimension of the strike head 24. In theextended condition of the push button member, as shown, the inner endsof the wedging fingers 41 just enter the space between the rollers 35without exerting any spreading force. The extreme ends of the fingersare sharply tapered and will engage the rollers both above and below thestrike the head of which is of course accommodated in the relativelypenetrating latched condition by the vertical separation of the fingers.The top and intermediate flanges 28, 29 of the bracket 27 will affordsome guiding of the push button, with the fingers 41 respectivelyclosely adjacent the opposed surfaces thereof.

The latch is accordingly actuated to release the door for opening simplyby pushing the member 37 in by hand thereby causing the wedging fingers41 to spread the spring rollers 35 sufiiciently for disengagement withthe strike head 24. As the door is pulled open, the rollers 35 of coursewill move back to the close spaced normal condition immediately uponrelease of the force on the push button member 37, and this springreturn will be seen also to be effective to extend or move outwardly thepush button member to its normal full projecting position as shown. Theclosing of the door is of course accomplished in a swinging movementwhich aids the forcible closing against the seal without noticeableadded demand, and a very film and positively locked closure of the dooris provided by the disclosed mechanism.

The dishwasher is preferably also provided with an electric switchcontrol responsive to the opening and closing of the door, and theswitch provided for the purpose is shown as contained within a casing 42which is suitably mounted inside the top portion of the door laterallyadjacent the latch mechanism. The switch contact assembly and wiring areconventional, with an actuator in the form of a pin or plunger 43projecting from one side of the casing under a spring bias as is usualand to be depressed, for example, in this case to close normally opencontacts. With this switch connected in appropriate manner in thecontrol circuit for the dishwasher, the operation of the machine cantherefore be made dependent upon such actuation.

The switch is provided with an actuating leaf designated 44 generallyattached at one end to the switch casing 42 by a pivot 45 and extendingover the plunger 43 to engage and operate the same. This leaf is formedof two spring blades 46 and 47 having straight initial lengths which areplaced against each other and joined together to form a common sectionwhich extends from the end pivot connection beyond the point ofengagement with the switch plunger. The blades then separate to providetwo distinct free blade sections and the blades are, moreover, ofdifferent thickness to exhibit different spring characterisfiics. Moreparticularly, the blade 45 which is relatively to the front is of suchthickness that its free section acts as a fairly heavy spring, while theother inner blade 47 is noticeably thinner and thus has a lighter springaction.

The light spring blade 47 is angled as shown to locate its free ends 48in the path of the strike head 24 to be deflected by the relativeadvance of the strike in moving to the latched condition in the keeperassembly. In looking down on the assembly as in FIG. 4, wherein themechanism is fully latched, the strike head 24 has deflected the springblade 47 from a normal position relatively to the right from that shownand this deflection has produced pivoting of the leaf 44 in acounterclockwise direction and thus against the plunger 43 to depressthe same and close the switch contacts to permit the usual machineoperation. When the latch is disengaged and the door opened, the returnof the freed spring blade 47 allows opening of the switch to disable themachine.

As indicated in the above, it is sometimes desirable to provide ananticipatory switch function for such a door, so that while the closingof the electrical contacts of the switch in the example given iseffected upon full engagement of the latch mechanism, the opening of theswitch contacts will be responsive to the initial actuation to effectthe release of the latch. In the illustrated embodiment of theinvention, this feature is provided by the heavier spring blade'46 andits arrangement in engagement with the shoulder at the inner end of thepush button member body section 40. Referring again to FIG. 4, it willbe apparent that depression of the push button directly acts on theheavy blade 46 and the relation to the lighter blade 47 as noted permitsthe former to overpower the latter and move the common leaf sectionsufficiently away from the switch plunger 43 to allow the plunger toopen the contacts.

It will also be appreciated that the push button form of releaseperferred does not detract from the attractive appearance of thedishwasher and, moreover, that the clean simple handle lines remainintact. The release movement is essentially in line and compatible withthe door manipulation, with no swinging levers or the like adding bothprojection and complication of the hand motion required.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described.

I, therefore, particularly point out and distinctly claim as myinvention:

1. Latch mechanism for a dishwasher door and the like confronting aframing surface, a strike member on one of said door and surface andkeeper means on the other for latching engagement with the strike memberin the closed door condition, said strike member having a foremost headportion with rearwardly diverging sides and a rearwardly contiguous bodyportion of such relatively reduced size as to define laterally spacedshoulders behind and respectively at such sides of the strike member,said keeper means including a pair of detents arranged at the sides ofthe strike member when the latter advances relative to the keeper meansfor the latching engagement therewith, said detents being in the form ofrollers the axes of which are normally substantially in right angularrelation to the strike member, spring means normally holding saidrollers at a spacing which is less than the width of the head portion ofthe strike member at the shoulder defining juncture thereof with thecontiguous body portion, the spring means yieldingly permitting therollers to separate for passage of said head portion and then movingthem inwardly behind the shoulders thereof to lock the strike member inthe keeper means, and push-button means for forcing the rollers apartwhen manually actuated sufliciently to permit relative withdrawal of thestrike member, said push-button means having spaced wedging fingerextensions which engage the end portions of the rollers at both sides ofthe strike member engagement therewith.

2. In combination with an automatic dishwasher and the like having a tuband a closure therefor, latch means for holding the closure in closedcondition against the tub, said latch means comprising a strike on oneof the tub and closure and cooperable keeper means on the other, thestrike and keeper means being relatively moved into lockinginterengagement upon full closing of the tub closure, manual releasemeans for disengaging the locked strike and keeper means to permitopening of the closure, switch means mounted on one of the tub andclosure for controlling operation of the dishwasher in response toclosing and opening of the door, first actuator means operated by thestrike for closing the switch and resiliently holding the same closed asa result of such locking interengagement of the strike and keeper means,and second actuator means separate from but operated by said releasemeans for opening the switch in response to initial movement of saidrelease means when operated to disengage the strike and keeper means andbefore full disengagement thereof, whereby an operating cycle of thedishwasher can automatically be interrupted in anticipation of openingof the tub closure.

3. The combination set forth in claim 2, wherein said release meansincludes a push-button actuator.

4. The combination set forth in claim 2, wherein said first actuatormeans is a relatively light first spring arm engaged and deflected bythe strike in such relative movement of the same, and the secondactuator means is a less flexible second spring arm actuated by therelease means to overpower the switch-closing force of said first springarm and thereby open the switch.

5. The combination set forth in claim 2, wherein the strike has a headof spear form and the keeper means includes spring-biased rollers whichare cammed apart by the strike head and engage therebehind to lock thestrike.

6. The combination set forth in claim 5, wherein the release meansincludes spaced fingers which engage the rollers at each side of thestrike head when locked and wedge the rollers apart to free the strike.

7. The combination set forth in claim 6, wherein the release meansfurther comprises a push-button actuator.

8. The combination set forth in claim 6, wherein the first actuatormeans is a relatively light first spring arm engaged and deflected bythe strike in such relative movement of the same, and the secondactuator means is a less flexible second spring arm actuated by therelease means to overpower the switch-closing force of said first springarm and thereby open the switch.

9. The combination set forth in claim 8, wherein the tub closure 'has ahandle, and said release means further comprises a push-button actuatorwhich projects through a portion of said handle.

References Cited UNITED STATES PATENTS 2,824,185 2/1958 Sevey 200-172 X2,934,074 4/1960 Low 134-58 2,502,607 4/1950 Vinton 292-23 2,605,6308/1952 Keeler. 2,857,191 10/1958 Buchholtz 292-77 X 2,896,641 7/1959Kautfman et al.

MARVIN A. CHAMPION, Primary Examiner.

US. Cl. X.R.

